Congenital cytomegalovirus (CMV) is more common than Down's syndrome, spina bifida and fetal alcohol syndrome, yet few women -- less than 15% -- know about the risk it poses to unborn children, Anna L. Pina, APRN, MSN, NP-C, of Tulsa, Oklahoma, said during a poster presentation.

Despite being the leading cause of mental retardation and disability in children, there are currently no national public awareness campaigns to educate expecting mothers about congenital CMV.

Since the late 1990s, some hospitals in Italy, Belgium and France routinely screened patients to detect primary CMV in pregnant women using avidity testing, but because there is no cure or vaccine for CMV, the United States has chosen not to screen.

“There is no cure for Down's syndrome, but we still offer screening,” Pina said. “Women should be educated about how to protect themselves against infection.”

One of the eight herpes viruses that causes human infection, CMV has an incubation period of 40 days and is characterized by periods of latency and reactivation and is permanent after initial infection. In immunocompetent adults, infected individuals can be asymptomatic or present with mono-like symptoms, albeit with a negative monospot.

As many as 30% to 50% of women of childbearing age have never been infected with CMV. Between 1% and 4% of U.S. women experience a primary CMV infection during pregnancy, with approximately 30% to 40% passing the infection on to the fetus.

Among infants who contract CMV while in the womb about 10% to 15% are born symptomatic, and 20% to 30% of symptomatic children die, according to Pina. Of those born asymptomatic, 5% to 15% will go on to develop sequelae later in life.

To avoid primary infection during pregnancy, clinicians should advise pregnant women to practice good hand hygiene, especially after changing diapers, as CMV is excreted in the urine and saliva.

“Also, advise pregnant women to avoid kissing children, even their own, on the lips and cheeks. Kiss them on the forehead instead,” Pina said. “Many women get CMV from their own children.”

To screen for CMV in pregnancy, clinicians can perform antibody tests for IgG and IgM antibodies. IgG persists throughout the lifespan, whereas IgM is detectable for up to six months after primary infection or reactivation of the virus.

Women with a positive antibody test should undergo IgG avidity. For primary infections contracted within the prior three months, tests will show <30% avidity. After 20 weeks gestation amniocentesis can be performed for polymerase chain reaction.

If a woman screens positive, clinicians should discuss therapy with intravenous immunoglobulin, which has been shown to reduce CMV symptoms in experimental studies.

“Any child who fails newborn hearing screening should be considered for congenital CMV testing,” Pina said.

Viral urine culture or urine PCR within the first three weeks of life is the gold standard for screening newborns. If a newborn tests positive, immediate referral to a pediatric infectious disease specialist is warranted to discuss valganciclovir to decrease hearing loss risk.

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